Extension-ladder



(No Model.) r C. PRIZELL.

v EXTENSION LADDER. N0. Z81,681. Patented July 24, 1883.

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NITED STATES PATENT OFFICE.

CHARLES FRIZELI, or BOSTON, MASSACHUSETTS.

EXTENSION-LADDER.

SPECIFICATION formingpart of Letters Patent No. 281,681', dated July 24, 1883.

Application filed May 14, 1883. (No model.)

' specifically defined in the appended claims.

This invention relates to .that class of ladders which are formed in two sections, which are so interlocked as to be telescopically ad justed for the purpose of increasing or decreasing the entire length, as circumstances may require; and it consists in the construction and combination of the divers devices embodied therein, as hereinafter more particularly and fully set forth and claimed.

In the accompanying drawings, Figure 1 is a front elevation of a ladder in two sections embodying my invention, the lower portion of the lower section and the upper portion of the upper section being broken away. Fig. 2 is a rear perspective View of Fig. 1. Fig. 3 is a detached sectional elevation, the section being taken as on line C, Fig. 1, and as viewed from the left therein. Fig. 4 is a transverse section taken as on line A, Fig. 1. Fig. 5 is a deards of the lower section of the ladder, and 3 3 are similar parts of the upper section of the ladder. Said bars 2 2 are united by the usual rungs, 5, and the bars 3 3 are in a similar manner united by rungs 6,which are of such length that bars 3, when thereby secured together, will rest upon rungs 5 and slide freely between said lower bars, 2, in the well-known manner. The two sections of the ladder are secured in relative positions by the clamping irons 4, which are inserted in the inner faces of standards 2, and are secured in place by rivets, as shown, said clamps receiving the standards 3, which slide freely between the hook of the clamps and rungs 5, in the usual manner.

For the purpose of raising, lowering, and securing at any desired height the upper section of the ladder, I employ the following devices: The lower rung, 6, of the upper section of the ladder is arranged to rotate freely in standards 3, and upon said rung are rigidly secured two hooks, 7, by means of a rivet passand the other below the rung the hook will be horizontal, or nearly so, as shown in Fig. 3. Two ropes, 1O 11, of suitable size, are secured to the eyes 9 of ring 8 by means of hooks 13, and said ropes are supported at the top of the lower section of the ladder by means of a double sheave-block, 12, suspended from a rung, 5, or by any other of the well-known pivotal supports, by which a rope is carried above the object on which it is employed to exert force, and from which it depends to the place where force is applied 'to it and when force is applied to ropelO, as shown in Fig. 3, hooks 7 are, by the partial rotation of the rung, thrown or swung out of the path of rungs 5, so that the top section may then be, by said rope 10, raised or lowered to the desired extent. Then the top section has been so raised or lowered, and it is desired to secure the same,

force is exerted upon cord 11 and cord 10 is released,when, by the counter-rotation of the rung, the hooks will be vibrated into the line of rungs 5, as shown in Fig. 2, and by slacking away upon rope 11 the moving or top section is lowered until the hooks encounter the first rung '5 below them, and by engaging the same suspend the top section, as shown in Fig. 1.

It will be obvious that the space between the lower rung, 6, and the next above should as much exceed the space between any other two rungs in either section as is the length of hooks 7, in order that when the upper section is supported by the hooks the rungs in the two sections shall coincide, as shown in Fig. 1.

I am aware that it is old and common to employ in ladders two sections secured together by clamps, as shown in my drawings, that a rotary rung in the sliding or upper section, having hooks secured thereon, is also old and well known, and that it is well known to 0p erate such rung and hooks by a chain or cord attached to a short arm projecting from one Ion side of said rung at right angles to the shanks of the hooks, and I make no claim to any of said parts or devices as such, my invention being confined to my peculiar construction, embodying a pivotal rung, hooks rigidly secured thereto, and the ring 8,with its opposite eyes, 9, (or, what is the same in practical effect, two short arms secured to the rung,) and two independent ropes, cords, or chains, respectively secured to said eyes, and passing over a support near the top of the lower section of the ladder; hence I claim as my invention- 1. In an extension-ladder, the combination of hooks 7 and ring 8, having eyes 9 on opposite sides thereof, mounted on a pivotal rung of the top section of the ladder, and arranged to be operated by independent ropes attached to said eyes, substantially as specified.

2. In an extension-ladder, the combination of a pivotal rung, 6, hooks 7 thereon secured,

block 12, and ropes 10 11, respectively secured to said rung on opposite sides thereof and rove through said block, whereby said rung may be rotated in opposite directions to engage or 2 5 CHARLES FRIZELL.

XVitnesses:

T. W. PORTER, EUGENE HUMPIIREY. 

